[WebAssembly] Remove debug names from symbol table

Get rid of DEBUG_FUNCTION_NAME symbols. When we actually debug
data, maybe we'll want somewhere to put it... but having a symbol
that just stores the name of another symbol seems odd.
It means you have multiple Symbols with the same name, one
containing the actual function and another containing the name!

Store the names in a vector on the WasmObjectFile when reading
them in. Also stash them on the WasmFunctions themselves.
The names are //not// "symbol names" or aliases or anything,
they're just the name that a debugger should show against the
function body itself. NB. The WasmObjectFile stores them so that
they can be exported in the YAML losslessly, and hence the tests
can be precise.

Enforce that the CODE section has been read in before reading
the "names" section. Requires minor adjustment to some tests.

Patch by Nicholas Wilson!

Differential Revision: https://reviews.llvm.org/D42075

llvm-svn: 322741

1 files changed, 11 insertions, 14 deletions

diff --git a/llvm/lib/MC/WasmObjectWriter.cpp b/llvm/lib/MC/WasmObjectWriter.cpp
index ab44f8200a6..0fe04f188d7 100644
--- a/llvm/lib/MC/WasmObjectWriter.cpp
+++ b/llvm/lib/MC/WasmObjectWriter.cpp
@@ -221,6 +221,7 @@ class WasmObjectWriter : public MCObjectWriter {
       FunctionTypeIndices;
   SmallVector<WasmFunctionType, 4> FunctionTypes;
   SmallVector<WasmGlobal, 4> Globals;
+  unsigned NumFunctionImports = 0;
   unsigned NumGlobalImports = 0;
 
   // TargetObjectWriter wrappers.
@@ -252,6 +253,7 @@ private:
     FunctionTypes.clear();
     Globals.clear();
     MCObjectWriter::reset();
+    NumFunctionImports = 0;
     NumGlobalImports = 0;
   }
 
@@ -286,8 +288,7 @@ private:
                         ArrayRef<WasmFunction> Functions);
   void writeDataSection(ArrayRef<WasmDataSegment> Segments);
   void writeNameSection(ArrayRef<WasmFunction> Functions,
-                        ArrayRef<WasmImport> Imports,
-                        uint32_t NumFuncImports);
+                        ArrayRef<WasmImport> Imports);
   void writeCodeRelocSection();
   void writeDataRelocSection();
   void writeLinkingMetaDataSection(
@@ -852,11 +853,9 @@ void WasmObjectWriter::writeDataSection(ArrayRef<WasmDataSegment> Segments) {
   endSection(Section);
 }
 
-void WasmObjectWriter::writeNameSection(
-    ArrayRef<WasmFunction> Functions,
-    ArrayRef<WasmImport> Imports,
-    unsigned NumFuncImports) {
-  uint32_t TotalFunctions = NumFuncImports + Functions.size();
+void WasmObjectWriter::writeNameSection(ArrayRef<WasmFunction> Functions,
+                                        ArrayRef<WasmImport> Imports) {
+  uint32_t TotalFunctions = NumFunctionImports + Functions.size();
   if (TotalFunctions == 0)
     return;
 
@@ -1023,7 +1022,6 @@ void WasmObjectWriter::writeObject(MCAssembler &Asm,
   SmallVector<std::pair<StringRef, uint32_t>, 4> SymbolFlags;
   SmallVector<std::pair<uint16_t, uint32_t>, 2> InitFuncs;
   std::map<StringRef, std::vector<WasmComdatEntry>> Comdats;
-  unsigned NumFuncImports = 0;
   SmallVector<WasmDataSegment, 4> DataSegments;
   uint32_t DataSize = 0;
 
@@ -1113,8 +1111,7 @@ void WasmObjectWriter::writeObject(MCAssembler &Asm,
     const auto &WS = static_cast<const MCSymbolWasm &>(S);
 
     // Register types for all functions, including those with private linkage
-    // (making them
-    // because wasm always needs a type signature.
+    // (because wasm always needs a type signature).
     if (WS.isFunction())
       registerFunctionType(WS);
 
@@ -1131,8 +1128,8 @@ void WasmObjectWriter::writeObject(MCAssembler &Asm,
       if (WS.isFunction()) {
         Import.Kind = wasm::WASM_EXTERNAL_FUNCTION;
         Import.Type = getFunctionType(WS);
-        SymbolIndices[&WS] = NumFuncImports;
-        ++NumFuncImports;
+        SymbolIndices[&WS] = NumFunctionImports;
+        ++NumFunctionImports;
       } else {
         Import.Kind = wasm::WASM_EXTERNAL_GLOBAL;
         Import.Type = int32_t(PtrType);
@@ -1216,7 +1213,7 @@ void WasmObjectWriter::writeObject(MCAssembler &Asm,
               "function symbols must have a size set with .size");
 
         // A definition. Take the next available index.
-        Index = NumFuncImports + Functions.size();
+        Index = NumFunctionImports + Functions.size();
 
         // Prepare the function.
         WasmFunction Func;
@@ -1410,7 +1407,7 @@ void WasmObjectWriter::writeObject(MCAssembler &Asm,
   writeElemSection(TableElems);
   writeCodeSection(Asm, Layout, Functions);
   writeDataSection(DataSegments);
-  writeNameSection(Functions, Imports, NumFuncImports);
+  writeNameSection(Functions, Imports);
   writeCodeRelocSection();
   writeDataRelocSection();
   writeLinkingMetaDataSection(DataSegments, DataSize, SymbolFlags,